14 Technical data and dimensions
14.1 General
Basis for the technical data of Pfeiffer Vacuum roots pumps
● Specifications according to PNEUROP committee PN5
● ISO 21360-1: 2016 “Vacuum technology - Standard methods for measuring vacuum-pump per-
formance - General description”
● Leak test to ascertain the integral leakage rate according to EN 1779: 1999 technique A1; with
100 % helium concentration, 10 s measurement duration
● Sound pressure level: distance to vacuum pump 1 m
mbar
bar
Pa
hPa
kPa
Torr | mm Hg
mbar
1
1 · 10
-3
100
1
0.1
0.75
bar
1000
1
1 · 10
5
1000
100
750
Pa
0.01
1 · 10
-5
1
0.01
1 · 10
-3
7.5 · 10
-3
hPa
1
1 · 10
-3
100
1
0.1
0.75
kPa
10
0.01
1000
10
1
7.5
Torr | mm Hg
1.33
1.33 · 10
-3
133.32
1.33
0.133
1
1 Pa = 1 N/m
2
Tbl. 9:
Conversion table: Pressure units
mbar l/s
Pa m
3
/s
sccm
Torr l/s
atm cm
3
/s
mbar l/s
1
0.1
59.2
0.75
0.987
Pa m
3
/s
10
1
592
7.5
9.87
sccm
1.69 · 10
-2
1.69 · 10
-3
1
1.27 · 10
-2
1.67 · 10
-2
Torr l/s
1.33
0.133
78.9
1
1.32
atm cm
3
/s
1.01
0.101
59.8
0.76
1
Tbl. 10:
Conversion table: Units for gas throughput
Special versions
The technical data and dimensions for the vacuum pump refer to the specified standard
version.
● For deviations in special versions, please refer to the rating plates or the enclosed in-
formation.
14.2 Technical data
Type designation
Okta 250
Okta 250 M
Version
Standard with motor Standard with motor and
magnetic coupling
Differential pressure at the overflow valve
75 hPa
75 hPa
Connection flange (in)
DN 63 ISO-F
DN 63 ISO-F
Connection flange (out)
DN 63 ISO-F
DN 63 ISO-F
Nominal pumping speed
145 – 440 m³/h
145 – 440 m³/h
Nominal pumping speed at 50 Hz
290 m³/h
290 m³/h
Nominal pumping speed at 60 Hz
350 m³/h
350 m³/h
Input voltage 50 Hz
230 / 400 V
230 / 400 V
Input voltage 60 Hz
265 / 460 V
265 / 460 V
Input voltage: tolerance
±5 %
±5 %
Technical data and dimensions
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